1. Field of the Invention
This invention relates to a lens moving device, and more particularly, to a moving device for a zoom lens.
2. Description of the Prior Art
The lens moving device in a lens mounting mechanism, having a body tube with a longitudinally elongated guide slot, an operating member axially movable for carrying out zooming, an axially movable sleeve drivingly connected to the operating member, and a member for holding an optical lens with cam-pin means for moving the lens holding member in response to movement of the sleeve, is shown in U.S. Pat. No. 4,273,423.
In the above-described mounting mechanism, to limit the range of axial movement of the sleeve, use may be made of a key member movably fitted in the guide slot of the body tube and fixedly secured to the movable sleeve.
In this case, it is unavoidable that as the operating member or the zoom ring, is driven to move by a strong force, when it reaches the terminal end, a large shock is given to that key member, and that it bears a load to restraining the movable sleeve from rotation about the optical axis.
Further, recently, the trend of using synthetic resin for making up some of the constituent parts of the lens mounting mechanism by molding techniques, with advantages that mass production is facilitated, the production cost is reduced, the quality is uniformed from item to item, and the weight of the lens mounting is reduced, is becoming prevalent. This is valid in the case of the above-described lens mounting mechanism.
When the molding technique is applied to the above-described key member, body tube and movable sleeve, however, shortcomings, such as loss in the precision accuracy of the dimensions of each part and large decrease in the physical strength, are encountered.